<!DOCTYPE html>
<html style="margin:2em;color:red">
<head>
<meta charset="UTF-8">
<script>

function boom()
{
    document.documentElement.offsetHeight;
    document.body.style.position = "fixed";
    document.documentElement.offsetHeight;
    document.documentElement.style.MozBoxSizing = "border-box";
    document.documentElement.offsetHeight;
}

</script>
</head>
<body style="display: contents;" onload="boom();"><li style="color:lime">LI</body></html>
